Cardiac Power and Ventriculo-Arterial Coupling

Abstract

In health the heart pumps at maximal external power and efficiency (ratio of Power Output and O2 consumption) with an efficiency of about 25%. Whether the heart is pumping at optimal efficiency or optimal power (ventriculo-arterial coupling), or neither, depends on both the cardiac and the arterial state. To test if efficiency is maintained in disease ventriculo-arterial coupling analysis can be used. The slope of the ESPVR (Ees, see Chap. 14) characterizes the ventricle and the effective arterial elastance (Ea), which approximately equals total peripheral resistance over heart period, R/T, characterizes the arterial system. When Ees/Ea ≈ 1–2, external work is maximized, and cardiac efficiency close to maximal.